Introduction
Power improvement products are not easy for average consumers to get their minds around. There are many different philosophies on how to do it right, with few agreeing on what’s best. Questions on power correction come my way quite often, with most people wondering if they even need better AC and, if so, how much they need to spend to fix the problem.

To exacerbate the issue, bad power is not always something that you hear and can determine needs improving, but rather an area that, once you correct it, you’ll wonder why it took you so long to fix.

The Transparent PowerIsolator 8 is a reference-level power-conditioning device that provides eight hospital-grade outlets for your precious AV gear. It is available only in a black-brushed finish and retails for $2,995. The Transparent PowerIsolator 8 is a much sleeker-looking product than Transparent conditioners of past. The PowerIsolator 8 measures a slim 2U rack height of three-and-one-half inches tall by 17 inches wide and 19-and three-quarters inches deep. It comes complete with separate rack-mounting ears, in case you are so inclined.

The front of the unit has a rich-looking brushed machined plate with a tapering beveled edge that runs across the top and bottom of the bezel. At the center is a long window. Underneath are three LED lights indicating “Protection Active,” “Line Fault,” and “Isolation Active.” In the darkness of my room, I could see two green LEDs and faint red text reading “Transparent PowerIsolator 8.” The PI8 is packaged very well and is as solid as a block of metal. The fit and finish of this unit are outstanding, making the PI8 a welcome addition to my rack. At the back of the unit are four pairs of isolated outlets and a standard IEC power cord connector. The unit sits on four rubber feet, in case you choose to forego the rack-mounting and decide to shelf or stand-mount.

Technology
When it comes to technology, each company has its own spin on what
makes power perfect. The problem is that electrical engineers who are
not always music aficionados tend to design most power products.
Therefore, what is supposed to be perfect on paper is not always the
best-sounding solution. For this reason, I recommend that you don’t get
completely caught up in all the techno mojo, but rather give the best
products a listen when practical, and choose what sounds best to you.
Often, it’s the simpler designs that win the battle of sound.

Let’s talk about a couple issues that degrade AC power. Perhaps the
biggest is the noise that is generated from household appliances. These
can add significant noise to your line and degrade your AV experience,
smearing your soundstage and rendering your micro-dynamics, transients
and decay inaudible. To makes things worse, it doesn’t even need to be
your own household’s appliances, as noise will transfer across the
power lines. Most people have heard recommendations to install
dedicated power circuits in their home for their AV gear. Although this
is the best non-conditioned option, and it may give you more consistent
power, it will not remove most of the noise from the line. The fact is
that unconditioned power is always an issue. The only question is, how
much of an issue is it in your home?

There are a few different ways to combat these anomalies. Some choose
to regenerate power by comparing the incoming current to a reference
sine wave, and using an amplifier to recreate the wave. Although this
has many benefits, it also has issues, one of which is that you have
just reintroduced another amplifier into the line, one of the noisiest
components in a system. These units can get hot, are large and consume
energy; in some cases, they utilize tremendous amounts of power.

Another philosophy is power regulation. This can serve to ensure there
is always adequate current, yet it can be argued this does little,
because if your components see lower voltage, their power transformers
simply reach out and get more current. Another method is to filter the
line. This can be the least expensive method, yet it often provides the
worst results. Bad filtering will cause compressed dynamics and the
complete smearing of your precious soundstage.

You must be very careful when auditioning power-related products, due
to the fact that most, if not all, have positive attributes as well as
negatives. You will often hear improvements in one area and degradation
in another. For example, the midrange could be much improved, giving
you the impression that your sound is better, yet your dynamics and
bass response may be less defined and far less solid. Transparent has
taken a new approach to this age-old issue. Transparent’s PowerIsolator
8 employs an all-parallel circuit construction with all the electronic
components placed in parallel and no noisy printed circuit boards.

The PowerIsolator 8 provides eight outlets, or four pairs, each pair
having complete noise isolation. What this means is that you can plug
in your noisy digital gear, as well as sensitive electronics like your
AV preamp and amplifiers, without noisy cross-talk, something that most
power products do not provide. Additionally, the PI8 provides complete
surge protection without the considerable drawbacks you can expect from
the units at your local office supply store.

Background
For close to two decades, Transparent Audio has been manufacturing
audio and video cables at the very highest performance level. I have
used their speaker cables and interconnects, as well as their premium
video cable, in my reference system for close to 10 years. I spent many
years auditioning cables and settled on what I feel is the
best-sounding cable money can buy. Currently, I am running Transparent
Reference speaker cable and Reference interconnects. As for power, I
have reviewed everything from PS Audio and Audiophile APS to Exact
Power and many more, and have been referencing the Transparent
PowerIsolator 4 since Ed Masterson’s favorable review back in April of
2003. In my system, the PI4 is one of the best-sounding AC products,
albeit one of the lowest-tech, I have heard. The question remains, does
the PI8 improve upon the PI4 of past?

Set-up
For the evaluation of the Transparent PowerIsolator 8, I focused on
three distinct conditions, the first being untreated power coming from
my wall. I’ve found my untreated AC to be very average, having heard
both better and worse. The easiest way to evaluate the condition of
your untreated power is to measure the level of improvement you achieve
from AC conditioning: it’s that simple.The second set-up was with the
use of my longtime reference, the Transparent PowerIsolator 4. Lastly,
I connected the PowerIsolator 8 and auditioned the same musical pieces.
The music I selected was based on subtle nuances that could be achieved
with power improvement.